Headboard



FIG. 1 is a left front perspective view of a headboard showing my new design;

FIG. 2 is a front elevational view thereof; and,

FIG. 3 is a side elevational view, the opposite side being a mirror image thereof.

The bottom and rear views are not shown and form no part of the claimed design. The dashed lines represent environmental elements only and form no part of the claimed design. 

The ornamental design for a headboard, as shown and described. 